I experimented with with lib.i. This is untested, but it's what I have so far:

/* lib.i */ % module libspace %{

    #include "lib.h"
    extern x_space * new_space();
        extern void destroy_space( x_space * space );

        #ifdef PERL_OBJECT
        #define MAGIC_CLASS _wrap_libspace_var::
        class _wrap_libspace_var : public CPerlObj {
    public:

        #else
        #define MAGIC_CLASS
        #endif
        SWIGCLASS_STATIC
            int swig_magic_readonly( pTHX_ SV * SWIGUNUSEDPARM(sv),
            MAGIC * SWIGUNUSEDPARM(mg) ) {
            MAGIC_PPERL croak("Value is read-only.");
                return 0;
            }

            #ifdef PERL_OBJECT
        };

        #endif

        #ifdef __cplusplus
        extern "C" {

        #endif
        XS(_wrap_new_space) {
            {   x_space * result = 0;
                    int argvi = 0;
                    dXSARGS;

                    if ( ( items < 0 ) || ( items > 0 ) ) {
                    SWIG_croak("Usage: new_space();");
                }
                result = ( x_space * ) new_space();
                    ST(argvi)
                    = SWIG_NewPointerObj( SWIG_as_voidptr(result),
                    SWIGTYPE_p_x_space, 0 | 0 );
                    argvi++;
                    XSRETURN(argvi);
                fail:
                    SWIG_croak_null();
            }
            }

            XS(_wrap_destroy_space) {
            {   x_space * arg1   = ( x_space * ) 0;
                    void * argp1 = 0;
                    int res1  = 0;
                    int argvi = 0;
                    dXSARGS;

                    if ( ( items < 1 ) || ( items > 1 ) ) {
                    SWIG_croak("Usage: destroy_space(space);");
                }
                res1 = SWIG_ConvertPtr( ST(0), &argp1, SWIGTYPE_p_x_sp
+ace,
                    0 | 0 );
                    if ( !SWIG_IsOK(res1) ) {
                    SWIG_exception_fail( SWIG_ArgError(res1),
                        "in method '" "destroy_space" "', argument " "
+1"
                            " of type '" "x_space *""'" );
                }
                arg1 = ( x_space * ) (argp1);
                    destroy_space(arg1);

                    XSRETURN(argvi);
                fail:

                    SWIG_croak_null();
            }
            } %}
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Does that help?